Plant Evolution
“If you are not a microbe and not
animal, then you are most likely a
plant”
-Biology4kids.com
Actual Plant Evolution
• Closest Common Ancestor
to Plants:
Multicellular Algae
Protist Evolution:
-Heterotrophic (Amoeba)
-Unicellular and
Autotrophic
(Euglena/Diatoms)
-Multicellular and
Autotrophic (Typical
Algae)
• So if Algae can be
multicellular, what
makes it a plant?
– Apical Meristem
promotes growth
– Multicellular Embryo
– Alternation of
Generations
Evolution of a Multicellular
Embryo
Protists--Very Diverse!
Evolution of Eukaryotic Cells
• Endosymbiosis
– Evidence:
• DNA
• Reproduce by Binary
Fission
• Size
• Double Membranes
Endosymbiosis
What do Charophycean algae and
plants have in common?
•
•
•
•
•
Homologous chloroplasts (they are green!)
Cellulose Cell Walls
Peroxisomes
Homologous Sperm
Molecular similarities (DNA)
Evolution of Main Groups of Plants
On your own
• Review:
– Alternation of Generations
– Reproductive Tissues
Plant Organization
• Organs
• Tissues
• Cells
Let’s look at some of the plant basics…
• In plants, there are three
major types of organs:
– Leaves
– Roots
– Shoots
• Note details in diagram
about roots and shoots
Modified Roots and Shoots
Modified Leaves
good things come in threes
• In plants, there are
three types of tissues:
• Dermal
– Cuticle--adaptation
• Vascular
– Xylem & Phloem
• Ground
– Key Functions
In plants, there are three types of
cells
• Parenchyma - think
“parent” (along with
metabolic functions)
• Collenchyma - weak
walls, growth
• Sclerenchyma -thick
walls, support, DEAD
Details of a Leaf
• Look at
the leaf as
an organ
and
identify
tissue and
cell types.
Unity and Diversity:
Angiosperms
Observations and Analysis in Lab notebooks
Introduction—What is the role of the leaf and how is it organized to perform the function of
photosynthesis.
Observations and Analysis-1.Wet mount of stomata. Label guard cells and identify purpose of stomatat.
2.Prepared leaf slide. Label and provide purpose of each tissue type.
Label: Epidermis (collenchyma), cuticle, mesophyll, palisade parencyhma, spongy
parenchyma, vascular bundle (schlerenchyma)
3.Monocot and Dicot stem
Compare and contrast the vascular tissue and be able to recognize the difference.
Then make a chart in your lab notebook showing the 5 major differences between
monocots and dicots.
Conclusion: Describe how the organization of a leaf allows for the emergence of the
funciton of photosynthesis.
Additional Resources on Plant
Diversity
• Book: Chapter 35-38; Chapter 28-30
• Private Life of Plants: Putting Down Roots
???When???
Friday:
Photosynthesis: Chapter 10